Tests seem good, but recurring "stuff" on the floor

[glamaina]

Ive been battling this brownish looking stuff (see pics) accumulating on the floor of my pool for a few months. Although the pics makes it look more green then in real life. Its only on the floor, not the walls and accumulates in the ripples of the liner very slowly. I have vacuumed it out to waste 4 times now. Initially I thought it was sand that wasn't filtering, then I thought it was mustard algae then I thought it was pollen. I officially have no idea what it is.

That's when I found this place, read every section many times and took things into my own hands. Whats screwing me up I think, is that I went away for 2 weeks and relied solely on chlor tabs in my chlorinator (which I don't use anymore normally). My CYA is now 90 and I try to keep my FC up around 10-12

My test this morning

FC = 8.5
CC = .2
TA = 100
PH = 7.5

I cannot get my CC to be 0. It has been .2 for a few months however the SLAM process says that once under .5 you should be good. I can tell you that I lost 2ppm chlorine over night last night. from 10.5 to 8.5 so im not sure if that indicates a problem. The brown stuff is slowly reappearing again after my last vacuum and when I brush the floor of the pool some spots have a little cloud of stuff come up even with no visible algae present.

Any suggestions. Should I SLAM it again and wait till the overnight change is only 1ppm? Should I drain the pool to get the CYA down first?

thanks for the help.

 

[JVTrain]

The pictures and the OCLT indicate that you have some residual algae that can only be cleared out with a SLAM. That will clear up your algae problem. However, you have high CYA. I would recommend draining 50% of the pool to lower CYA, then complete the SLAM. It will be much easier to achieve and maintain shock level FC for the process if you drain/refill before SLAMing.

 

[JVTrain]

I'm also assuming that the material on the bottom puffs up and almost disappears into the pool when it is brushed, as algae does.

 

[glamaina]

It does puff up and disappear, however doesn't pollen do the same and also look brownish? Although seems late in the year for pollen issues.

 

[pooldv]

The Overnight Chlorine Loss Test is the best tool to determine if a SLAM is needed.

 

[kcindc]

FYI, the criteria for completing a SLAM includes the CC of 0.5 or less, but it also includes crystal clear water free of algae.

The criteria for needing to SLAM is any of the following: visible presence of algae, CC > 0.5 or failing the OCLT.

 

[domct203]

You've failed an OCLT & have what appears to be visible algae.

It would be best to drain to lower CYA and SLAM. The longer you wait, the more time the algae will have to reproduce.